JPH0634005Y2 - Descaling device consisting of suction valve and plunger pump with unloader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a descaling device using a plunger pump for removing the surface scale of a workpiece sent out from a hot rolling process. is there.

(Prior Art) A descaling device including a so-called plunge pump that produces high-pressure water by a plunge pump and sprays the high-pressure water onto the surface of a workpiece sent out from a rolling process to remove scale is known. .

Also, since the work material sent out from the rolling process is intermittent, the descaling work is performed intermittently according to the flow, that is, while the work material is not sent out from the rolling process, the plunger The pump is run dry,
There is also known a descaling device incorporating a device for controlling the switching of the plunger pump to the actual operation only while the work material is delivered. More specifically, the unloader mechanism that forcibly holds the suction valve of the plunger pump in the open state based on a signal from the outside is installed while the workpiece is not sent out from the rolling process.
By the action of this unloader mechanism, the suction valve is opened, and the pressure in the cylinder of the pump and the pressure in the suction pipe are kept at the same pressure, that is, the liquid can freely flow in and out of the cylinder and the suction pipe. In addition, a descaling device with a so-called suction valve / unload mechanism is also known in which the pump is idled (unloaded) without discharging liquid from the discharge valve. Incidentally, the technique disclosed in Japanese Patent Application No. 59-209949 (Japanese Patent Publication No. 3-19917) relating to the present applicant is one example.

FIG. 2 is a piping system diagram of a descaling device including a plunger pump incorporating a suction valve unloader mechanism (not shown because it is known).

As shown in this figure, the descaling device consisting of a suction valve / plunger pump with an unloader pumps up water with a base pump 2 from a water supply tank 1, and pumps up the water through a strainer 8 and a suction side main pipe 3. To the injection valve 6a, 6b, 6c arranged in the descaling stand through the discharge side main pipe 5 to the injection valve 6a, 6b, 6c. It is usually configured to control the opening and closing of ... to inject the material to be processed sent out from the rolling process.

Further, a cushion tank 7 is connected to the suction side main pipe 3 in order to compensate for a water hammer phenomenon that occurs in the suction side main pipe 3 system and a shortage of the suction amount of the plunger pump 4 due to the start and stop of the plunger pump 4. The unloader mechanism (not shown) is incorporated in the suction valve of the plunger pump 4. Further, a check valve 10 is provided on the main pipe 5 on the discharge pipe side.
A bypass line 11 is connected between the check valve 10 and the plunger pump 4, and the bypass line 11 is provided with a booster valve 12 whose opening can be adjusted.

By operating the booster valve 12 in the bypass line 11, a water hammer due to a sudden pressure increase of the discharge side main pipe 5 at the time of starting of the descaling device, that is, at the time of rising, and an end connected to the discharge side main pipe 5. It is designed to reduce the impact on the equipment and to maintain the rise due to the gentle pressure rise.

Further, a gas-liquid contact type accumulator 15 is provided between the check valve 10 and the high pressure water injection valves 61, 6b, 6c ...
A pressure detector 16 which detects the internal pressure of the accumulator 15 and sends a control signal to the suction valve / unloader incorporated in the plunger pump 4.
And controller 17 are connected. In other words, when the internal pressure of the accumulator 15 changes due to the injection and non-injection of high-pressure water, the change in the internal pressure is detected, the suction valve unloader incorporated in the plunger pump 4 is operated, and power for driving the plunger pump 4 and It is configured to achieve the energy saving effect of water.

The branch pipe 9 shown in FIG. 2 is for taking out utility water from the apparatus, and 13 is a safety valve provided in the bypass line 11. Furthermore, the accumulator
The pressure switch 18 provided on the discharge side main pipe 5 leading to 15 is located in front of the accumulator 15 when the pressure of the discharge side main pipe 5 and the specified internal pressure of the accumulator 15 become almost the same when the descaling device starts up. Is for opening the shut-off valve 14 at, and 19 is also for temporarily unloaded (unloading) the plunger pump 4 when the pressure of the discharge side main pipe 5 reaches the specified pressure at the time of starting. It is a pressure switch for switching to.

Therefore, when the descaling work is started by this descaling device, first, as can be seen at the time of starting a general high pressure device, a preparatory operation according to the following procedure is carried out and then the operation is shifted to the operation. .

(1) First, the booster valve 12 of the bypass line 11 of the discharge side main pipe 5 of the descaling device is fully opened, and the high pressure water injection valves 6a, 6b, 6c ... Are fully closed. Then, the plunger pump 4 is started. That is, the plunger pump 4 is started in the unloaded state.

(2) Next, the plunger pump 4 is switched to the load state, that is, the on state.

Then, the pressure-increasing valve 12 provided in the bypass line 11 is gradually narrowed down to bring the pressure of the discharge side main pipe 5 close to the internal pressure of the accumulator 15 (gas pre-pressure of the accumulator, for example, 170 kgf / cm ² ), so that both pressures are almost the same. Boost up until.

(3) When the pressure of the discharge side main pipe 5 becomes almost the same as the internal pressure of the accumulator 15, the throttle of the booster valve 12 of the bypass line 11 is temporarily stopped.

(4) When the internal pressures of the discharge main pipe 5 and the accumulator 15 become almost the same, the shutoff valve 14 provided in front of the accumulator 15
Is automatically opened by the operation of the pressure switch 18. As a result, the discharge side main pipe 5 and the accumulator 15 are communicated with each other.

That is, the plunger pump 4 and the accumulator 15 are communicated with each other.

(5) When the plunger pump 4 and the accumulator 15 are communicated with each other, another pressure switch 19 provided on the discharge side main pipe 5 is activated to switch the plunger pump 4 from the loaded state to the unloaded state. That is, the plunger pump is switched from the on-load state to the unload state.

(6) At the time when the plunger pump 4 is switched to unloading, the booster valve 12 of the bypass line 11 is completely closed and the preparation for starting as a descaling device is completed.

After that, if the injection valve is opened / closed according to the path of the workpiece sent out from the rolling process, the internal pressure of the accumulator 15 changes accordingly, so the pressure detector 16 detects the internal pressure change, The controller 17 operates based on the detection signal, the suction valve unloader incorporated in the plunger pump 4 is automatically controlled and operated, and the efficient and energy-saving descaling work is continued.

(Problems to be solved by the invention) As described above, the conventional descaling device including the suction valve and the plunger pump with the unloader is
In order to prevent damage to the piping system and equipment due to a sudden increase in pressure during startup, and other problems, a bypass line with a booster valve is installed, or a shutoff valve is installed immediately before the accumulator. The incidental structure such as valves is complicated.

As a result, the conventional descaling device has a drawback that the design of a so-called sequence control system for performing intermittent descaling work from the start of the device itself is complicated.

An object of the present invention is to provide a descaling device composed of a plunger pump with a suction valve capable of performing a safe and smooth descaling work by solving the drawbacks of the conventional device. In particular, the aim was to simplify the configuration of the equipment piping system and control system.

(Means for Solving the Problem) As a means for achieving the above object, the technical means of the present invention is characterized in that it is provided in the discharge side main pipe of a descaling device including a suction valve and a plunger pump with an unloader. A bladder type accumulator is connected between the check valve and the injection valve, and the suction valve installed in the plunger pump detects the pressure of the discharge side main pipe between the bladder type accumulator and the discharge side main pipe. The unloader is provided with a pressure transmitter including a pressure switch and a controller for sending a control signal of the load of the plunger and a control signal of no load.

That is, instead of the conventional gas-liquid contact type accumulator,
It is characterized in that a so-called bladder type accumulator equipped with a rubber bag for partitioning gas and liquid and having a poppet valve on the inlet side is incorporated.

(Operation) In the present invention, as described above, since the bladder type accumulator is incorporated in the discharge side main tube instead of the conventional gas-liquid contact type accumulator, when the device is first started, that is, when it is started up, When the plunger pump is started with the injection valve fully closed, the pressure applied to the discharge side main pipe first pushes up the poppet valve of the bladder type accumulator. As a result, the increased pressure is absorbed by the bladder type accumulator. That is, the rapid pressure rise of the discharge side main pipe is alleviated.

Next, when the pressure in the main pipe on the discharge side reaches the specified pressure, the suction valve unloader built into the plunger pump is operated in sequence by the pressure transmitter connected to the front of the bladder type accumulator and the controller. To operate intermittently.

That is, by controlling the opening and closing of the injection valve according to the path of the work material sent out from the rolling process, the plunger pump automatically turns the suction valve on and off, and it is smooth and safe according to the path of the work material. Descaling work can be retained.

(Embodiment) FIG. 1 is a piping system diagram of a descaling device showing an embodiment of the present invention. The difference from the conventional descaling device shown in FIG. 2 is that the accumulator is switched to a bladder type accumulator 20. In point.

21 is a rubber bag mounted inside the bladder type accumulator 20, 22 is a poppet valve on the inlet side,
The other devices are exactly the same as the conventional case.

However, since the bladder type accumulator 20 is used, the shutoff valve 14 at the inlet of the accumulator 15 in the conventional apparatus shown in FIG. 2 is not necessary. Further, in the case of the conventional device, the bypass line 11 provided with the pressurizing valve 12 was provided for the purpose of alleviating a sudden pressure increase in the discharge side main pipe at the time of starting, but this is also unnecessary. Other pressure switches 18 and 19 are also unnecessary.

(Effect of the Invention) As described above, the descaling device including the plunger valve pump with the suction valve unloader according to the present invention has a rubber bag inside instead of the conventionally used gas-liquid contact type accumulator and has a poppet valve at the inlet. The use of a bladder type accumulator with the simplification of the discharge side piping system eliminates the need to provide a bypass line with a booster valve for suppressing a sudden pressure rise in the discharge side piping system at the time of conventional startup. It was

Next, in the case of the conventional gas-liquid contact type accumulator, it was necessary to provide a shutoff valve on the inlet side, but in the present invention, since the poppet valve is incorporated in the accumulator,
That is also unnecessary. Therefore, the piping system of the entire device is simplified.

In particular, in the case of the conventional device, as a means for mitigating a sudden pressure increase at the time of starting, the booster valve provided in the bypass line was constituted by an electromagnetic opening / closing valve, which was electrically controlled to open / close. Although the control system for sequentially controlling the entire apparatus including the system was complicated, in the present invention, it was extremely simplified and greatly contributed to the reduction of apparatus cost and trouble.

[Brief description of drawings]

FIG. 1 is a piping system diagram of a descaling device comprising a plunger pump with a suction valve unloader according to the present invention, and FIG. 2 is a conventional piping system diagram. 1 ... Water tank, 2 ... Base pump 3 ... Suction side main pipe, 4 ... Plunger pump 5 ... Discharge side main pipe 6a, 6a, 6c ... Injection valve 7 ... Cushion tank 8 ... Strainer, 9 …… Branch pipe 10 …… Check valve, 11 …… Bypass line 12 …… Boosting valve, 13 …… Safety valve 14 …… Shutdown valve, 15 …… Accumulator 16 …… Pressure detector, 17 …… Controller 18, 19 …… Pressure switch 20 …… Bladder type accumulator 21 …… Rubber bag, 22 …… Boppet valve

Claims (1)

[Scope of utility model registration request] 1. A suction valve of a plunger pump is assembled with a suction valve unloader for controlling the opening and closing of the suction valve according to a control signal, and a check valve and an injection valve are provided on the discharge pipe side. A descaling device with a suction valve and unloader for projecting high-pressure water to the workpiece sent out from the rolling process to perform descaling work, and between the check valve and the injection valve provided in the discharge pipe. The bladder type accumulator is connected to the bladder type accumulator, and between the bladder type accumulator and the discharge pipe, a pressure detector for detecting the pressure of the discharge pipe and a suction valve unloader based on a detection signal from the pressure detector are connected to the suction valve unloader. A death valve consisting of a plunger pump with suction valve and unloader, which is equipped with a controller that sends an open / close control signal. Calling equipment.